#include<stdio.h>
int main()
{
	double a,b,c;
	a=5000;
	b=0;
	while(a){
		a=a*1.0032;
		b++;
		a=a+5000;
		if(a>=600000)
		break;
	}
	c=b/12;
	printf("%lf",c);
	return 0;
 } 
